This invention relates to new and useful improvements in draft control and tail beam devices for ground working discer type agricultural implements.
Conventionally, the tail beam and associated rudder wheel maintains the draft angle of the discer as it is pulled by the tractor at an angle to the direction of travel and this angle is maintained by means of a heavy-duty spring extending between the rudder wheel assembly and the tail beam. However, springs have an unfortunate characteristic namely that the resistance increases as the spring is expanded so that there is a relative lack of resistance at the first portion of travel of a heavy-duty tension spring.
While this does not effect the breaking away of the rudder wheel assembly during turning operations, nevertheless it is unsatisfactory when used in the operating position particularly when varying conditions of ground are encountered.
For example, if the disc gangs are set at a predetermined depth in relatively soft ground and the machine is tracking satisfactory being maintained by means of the rudder wheel engaging the side of the furrow, then if a patch of hard ground is encountered, the disc gangs tend to elevate relative to the ground surface thus relieving the pressure and permitting the machine to "run out." The spring between the rudder wheel assembly and the tail beam does not have sufficient strength in its initial expansion to maintain the rudder wheel assembly in the correct relationship so that the entire setting of the machine is disturbed.
The reverse is also true. Namely, if tilling relatively firm ground, and a soft patch is reached, the discs dig deeper and the draft is upset because the rudder wheel assembly cannot maintain the correct angular relationship.
Another disadvantage occurs particularly when the device is being used on side hills or uneven terrain under which circumstances the rudder wheel assembly with a spring connection is not sufficient to maintain the sideward movement of the discer.